Carbon nanotube field emitter and preparation method thereof

Abstract

A method for making a carbon nanotube field emitter is provided. At least one carbon nanotube wire and at least two electrodes are provided. The at least one carbon nanotube wire is heated to form at least one graphitized carbon nanotube wire. The at least one graphitized carbon nanotube wire comprises a first end and a second end, and the first end is opposite to the second end. The at least two electrodes are welded to fix the first end between the at least two electrodes. welding the at least two electrodes to fix the first end between the at least two electrodes. The second end of the at least one graphitized carbon nanotube wire is exposed from the at least two electrodes as an electron emission end.

What is claimed is: 
     
       1. A method for making a carbon nanotube field emitter, comprising:
 S 1 , providing at least one carbon nanotube wire and at least two electrodes; 
 S 2 , heating the at least one carbon nanotube wire to form at least one graphitized carbon nanotube wire, wherein the at least one graphitized carbon nanotube wire comprises a first end and a second end, and the first end is opposite to the second end; and 
 S 3 , welding the at least two electrodes to fix the first end between the at least two electrodes, wherein the second end of the at least one graphitized carbon nanotube wire is exposed from the at least two electrodes, the second end is an electron emission end. 
 
     
     
       2. The method of  claim 1 , wherein the first end of the at least one graphitized carbon nanotube wire is fixed between the at least two electrodes by spot welding or laser welding. 
     
     
       3. The method of  claim 1 , wherein the first end of the at least one graphitized carbon nanotube wire is fixed between the at least two electrodes by a spot welding method, the spot welding method comprising steps of:
 S 311 , placing the first end of the at least one graphitized carbon nanotube wire between the at least two electrodes, wherein each of the least two electrode clamps the at least one graphitized carbon nanotube wire, and the second end is exposed to form an emission unit; 
 S 312 , placing the emission unit between a fixed welding head and a movable spot welding head, and driving a pressure driving device to press the movable spot welding head against the fixed spot welding head; and 
 S 313 , controlling a spot welder output a voltage and a current to weld the at least two electrodes together to fix the first end of the at least one graphitized carbon nanotube wire. 
 
     
     
       4. The method for making a carbon nanotube field emitter of  claim 1 , wherein the first end of the at least one graphitized carbon nanotube wire is fixed between the at least two electrodes by a laser welding method, the laser welding method comprising steps of:
 S 321 , placing the first end of the at least one graphitized carbon nanotube wire between the at least two electrodes wherein the each of the at least tow electrodes clamps the at least one graphitized carbon nanotube wire, and the second end is exposed to form an emission unit; 
 S 322 , clamping and fixing the emitting unit with a clamp; and 
 S 323 , welding the at least two electrodes by laser irradiation to fix the first end of the at least one graphitized carbon nanotube wire. 
 
     
     
       5. The method for making a carbon nanotube field emitter of  claim 1 , further comprising a step of cutting the second end of the at least one graphitized carbon nanotube wire with a laser after S 3 . 
     
     
       6. The method for making a carbon nanotube field emitter of  claim 5 , further comprising a step of ultrasonically cleaning the second end of the at least one graphitized carbon nanotube wire. 
     
     
       7. The method for making a carbon nanotube field emitter of  claim 1 , further comprising a step of depositing a carbon layer on a surface of the at least one graphitized carbon nanotube wire after S 2 . 
     
     
       8. A carbon nanotube field emitter, comprising:
 at least one emission, comprising at least two electrodes and at least one graphitized carbon nanowire, wherein the at least one graphitized carbon nanowire comprises a first end and a second end opposite to the first end, the first end of the at least one graphitized carbon nanowire is fixed between the at least two electrodes, and the second end of the at least one graphitized carbon nanowire is exposed from the at least two electrodes, the second end is an electron emission end. 
 
     
     
       9. The carbon nanotube field emitter of  claim 8 , wherein the carbon nanotube field emitter comprises a plurality of the emission units, and the plurality of the emission units are stacked and welded together. 
     
     
       10. The carbon nanotube field emitter of  claim 8 , wherein the at least one graphitized carbon nanotube wire is an untwisted carbon nanotube wire or a twisted carbon nanotube wire. 
     
     
       11. The carbon nanotube field emitter of  claim 8 , wherein each of the at least one emission unit comprises a plurality of graphitized carbon nanotube wires, and the plurality of graphitized carbon nanotube wires are spaced apart from each other and fixed between the at least two electrodes. 
     
     
       12. The carbon nanotube field emitter of  claim 8 , wherein the carbon nanotube field emitter comprises a carbon layer, and the carbon layer is uniformly coated on a outside surface of the at least one graphitized carbon nanotube wire.